好奇为什么 · 4-8 岁

热气球为什么能飞

热空气的轻轻托举

科普启蒙约 5 分钟4-8 岁中英双语

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热气球节上，小雨仰头问：它为什么能飞？

At the hot-air balloon festival, Yu looks up and asks, “Why can it fly?”

热气球节上，小雨仰头问：它为什么能飞？

At the hot-air balloon festival, Yu looks up and asks, “Why can it fly?”

妈妈牵着她站在安全线后，看着工作人员加热球囊。

Her mother holds her hand behind the safety line as trained staff heat a balloon.

火焰加热空气，空气膨胀，分子之间更松散。

The flame warms the air. It expands, with its molecules spread farther apart.

所以同样大小的球囊里，热空气密度更低，但仍有重量。

So in the same-sized balloon, the hot air is less dense, but it still has weight.

球囊外的冷空气更密，会向上托住它。

The cooler, denser air outside pushes upward all around the balloon and lifts it.

浮力大过球囊、篮子和人的总重量，热气球就上升。

When the upward lift is greater than the weight of the balloon, basket, and people, it rises.

冷却或放出热空气，浮力变小，热气球便慢慢下降。

When the air cools or hot air is released, the lift becomes smaller and the balloon slowly descends.

小雨点点头：那鸟儿为什么也会飞呢？

Yu nods. “Then why can birds fly too?”

热空气膨胀后密度变小，外面的冷空气浮力足够大时，热气球就会上升。

Warm air is less dense; when outside air provides enough buoyancy, a hot-air balloon can rise.

将当前插图、字幕和旁白合成为适合手机分享的竖屏视频。

让孩子走进这个故事

生成一本以孩子为主角的「热气球为什么能飞」新编绘本，或写下任何一个小心愿，几分钟做成专属中英双语绘本。